The present invention relates to hoisting apparatus and in particular to a vehicle having a hoisting apparatus mounted thereon which is preferably used in the lifting of oil well tubing.
Hoisting devices and vehicles having movable derricks or booms of various designs have long been used to lift objects. Although many such hoisting device designs utilize a telescoping boom, this telescoping action is normally only utilized to extend and position the boom and not to perform other functions. In oil well operations a winch or rotating drum assembly is used to raise or lower the lifting cable that is placed out over this telescoping boom. In such hoisting devices, some type of mechanical rotary drive must be used to power the winch. Since these telescoping booms usually use a hydraulic cylinder and piston to extend the boom, a separate hydraulic pump system must be provided in addition to the rotary drive.
Heretofore, vehicles having hoisting apparatus have been used in the lifting of oil well tubing during the repair or other maintenance of the oil well. Due to the great weight of the oil tubing being lifted and the other needs of the vehicle, such vehicles normally carry a large upright derrick or mast-like assembly. This derrick assembly is erected over the oil well to provide a support for the lifting cable. Normally, these vehicles use a rotary winch with this derrick to take up the lifting cable when lifting the tube. Each vehicles are very large since they are specifically designed to be used in the complete removal of oil tubing. To permit this complete removal, the derrick assembly must be sufficiently tall that an entire section of oil tube can be removed from the oil casing while supported from the derrick. These vehicles are very difficult to maneuver due to the large derrick assembly and are both expensive and difficult to transport, assemble and store.